1. Field of the Invention:
This invention relates to well tools and more particularly to tools for plugging well flow conductors and running tools and receptacles for such plugging tools.
2. Related Art and Information
In the past wells have oftentimes been plugged at or near the lower end of the well tubing for preventing production, or to permit bleeding the tubing pressure to that of the atmosphere so that the wellhead or a portion of the well tubing could be removed, or so that pressure applied above the plug could be used to test the tubing, set the packer, or test the packer.
Various types of plugs have been used for such tests. Generally, such plugs are installed in a landing receptacle, which forms a portion of the tubing string, through use of wireline equipment and techniques. Some plugs are designed to hold against high pressure from below, some are designed to hold overpressure from above, and some are designed as two-way plugs to withstand pressure differentials from either above or below. The latter type is often desirable since it will permit a greater variety of testing operations to be conducted.
Two-way plugs are well known in the oil industry. Suitable two-way plugs are available from Otis Engineering Corporation, Dallas, Tex., and are found illustrated in their General Sales Catalog "OEC 5338". They are the Otis Type PX, PR, PXN, PRN, and PRT Plug Choke Assemblies and the Type XX, RR, XXN, RRN, and RNT found on page 126 of that catalog. These plugs are designed for installation in Type X, XN, R, RN, or RNT Landing Nipples, shown on page 116 of the catalog, with the exception of the Type RNT Landing Nipple. The Type RNT Landing Nipple is the same configuration as the Type RN but with slightly smaller inside diameters. These plugs are generally run on running tools such as the RXN illustrated on page 307 of the catalog.
Type PN and PS Choke Assemblies are found on page 127 of the Otis Catalog. The letter "N" in the above used designations indicates a no-go device and of course a no-go device such as a Type PN must be installed in a Type N no-go landing nipple.
It is generally preferable that the lowermost landing nipple in a well be one of the no-go type.
Many of the plugs and landing nipples have been either premium-priced or too expensive to run and/or pull, sometimes requiring extra trips into the well with the wireline tools. More economical plugs and landing nipples have been desired, as well as cheaper, more dependable running tools.
Various landing receptacles, locking devices, plugs, and running tools are illustrated and described in the prior art patents listed below (one copy of each of which is being filed with this application for patent), as well as in the catalog referred to hereinabove.
______________________________________ Patents of the United States ______________________________________ 2,698,056 3,002,565 3,208,531 4,023,620 4,545,434 2,798,559 3,032,113 3,215,208 4,069,865 4,583,591 2,920,704 3,051,239 3,227,462 4,164,977 4,745,974 2,928,469 3,100,532 3,250,331 4,252,143 4,767,145 2,962,097 3,126,908 3,638,723 4,396,061 4,823,872 2,976,931 3,207,222 3,756,260 4,510,995 ______________________________________